The invention relates to a quick-action valve closed and opened by turning of about 90.degree. for pipes delivering liquid or gaseous medium.
There are quick-action valves supplementing the well-known good features of valves with quick operation. Such a valve is described for example in Hungarian Pat. No. 159,431 as the combination of the ball pivot and valve. In that valve the elastic tensioning of the valve member after its seating (which is a fundamental condition of the tight closing) is carried out by the applicant at medium pressure. According to Hungarian Pat. No. 156,529, the valve member is moved in the direction identical with the centerline of the valve seat by pressing in the balls at an angle. The same is carried out according to Hungarian Pat. No. 128,158 with a camshaft, and according to Hungarian Pat. No. 117,086 with an eccentric shaft. Hungarian Pat. No. 174,241 introduces a special valve that functions on the principle of bayonet locking. In Hungarian patent specification No. 166,856 a valve is described which turns as a flap and a mechanism that functions with hydraulic auxiliary energy.
A spherical valve, described in Hungarian patent specification No. 159,431, is not suitable for the tight closing of low-pressure media, or those where the flow direction is counter to the one designed. Thus it can be used only in special cases. The solutions described in Hungarian Pat. Nos. 156,529, 128,158, and 117,086 ensure adequate tensioning, but their common drawback is that the valve member can be lifted out only in the direction identical with the centerline of the valve seat, and even so only to a relatively slight extent; consequently the flow resistance of the valve is high. The apparatus according to Hungarian Pat. No. 174,241 lifts out the valve member in axial direction, but to a sufficient extent; on the other hand its construction and handling are difficult because of the axial-turning motion. The apparatus according to the Hungarian Pat. No. 166,856, as a result of the flap-type function, completely removes the valve member from the flow path, but its drawback is the difficult construction, incidental use of auxiliary energy, and its liability to failure.
The present invention is aimed at the realization of a solution, according to which the valve can be opened or closed by a single turn, it contains suitable mechanical advantage for the safe compression of the elastic valve member in closed position, it is capable while in open position of removing the valve member completely from the flow direction, and all these features are realized with a simple, safe apparatus without the need of auxiliary energy.
The invention is a quick-action valve, in which the valve member is fitted as a flap, i.e. it is fastened to a valve arm or similar structural element located outside the centerline of the valve seat and turnable around a main shaft perpendicular to the centerline. The valve includes an auxiliary shaft, the centerline of which is parallel with that of the main shaft, but it is arranged at an appropriate distance from it. An actuating arm, or similar rigid body, is rotatable around the auxiliary shaft, and fitted with a pressing element, suitably a roller (e.g., an axial ball bearing), the centerline of which is at a fixed instance from the auxiliary shaft. The roller engages a straight or nearly straight camming surface of the valve arm, or an auxiliary arm in rigid connection with the valve arm, so that upon full compression of the valve member, the camming surface in contact with the roller is perpendicular to the straight line interconnecting the center-lines of the roller and of the auxiliary shaft, i.e. a dead center position occurs. As a result of this construction, in the fully compressed position of the valve member a slight turn of the actuating arm brings about a much smaller displacement of the valve arm, which appears the other way round in the balance of forces. Hence a very high mechanical advantage will develop in the vicinity of the dead center position. This enables bringing about the high elastic compression force required for the safe, easy closing by hand through a small moment applied to the actuating arm.
Turning of the actuating arm is limited by a stop means fixed to, or on, the valve arm or to an auxiliary arm. The stop means is located to allow for the actuating arm to turn a few degrees past the dead center position, which results in the valve being self-holding in the closed position.
In a preferred construction an additional camming surface is formed on the valve arm or auxiliary arm symmetrically or nearly symmetrically with the first camming surface, which engages the roller when the valve is opened. The two camming surfaces are suitably the two side walls of a groove. In this construction an elastic stop element is inserted between the valve arm and valve case, or the auxiliary arm and valve case. The elastic stop is compressed in the open position of the valve. Thus in the fully open state, a dead center position a balance of forces exists that is similar to the fully closed state. Rotation of the actuating arm move than a few degrees beyond the dead enter position is prevented by a stop. Thus the open position of the valve is self-holding similarly to the closed position. The opening stop can be fastened to the valve case, or the valve arm, or an auxiliary arm.
In another embodiment, a spring, preferably a helical spring, or a weight-load, is connected to the shaft of the valve arm to turn the valve body in the opening direction. In this case there is no need for a second camming surface or for an elastic stop element compressed in the open state of the valve. On the other hand, opening of the valve is possible only by a force determined by the spring or weight-load, while this force has to be overcome for closing.
In a preferred version of of the above mentioned embodiment a conventional adjustable stop is mounted on the valve case to limit the movement of the actuating arm in the direction of opening, thus allowing the adjustment of open positions to a varying extent. This solution increases the advantageous features of the valve, in that the amount of the fluid medium flowing through the valve is finely adjustable.
According to a further preferred embodiment, the camming surface that supports the roller upon closing, is formed in such a way that when the valve body bears against the valve seat, the surface element in contact with the roller slightly slopes towards the closing direction, i.e. this surface-section is slightly concave. This enables the force transmission in this position to be similar to that of the positions closer to the dead center.